Electric circuit breaker



Re. 21,848v

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, 1937 4 Sheets-Sheet 4 G. BALACHOWSKY ELECTRIC CIRCUIT BREAKER Original Filed Feb. 4

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July 1, 1941.

. Inventor: Georges Bdachowsk XMM, l-Hs Attorheg.

Reuued July 1, 1941 UNITED STATES PATENT ori-*lcs ELECTRIC CIRCUIT BBEAKER Georges Balachowsky, Paris, France, assigner to General Electric Company, a 'corporation of New York Original No. 2,158,846, dated May 16, 1939, Serial No. 124,131, February 4, 1937.

Application for reisue May 9, 1941, Serial No. 392,742. In France February 27, 1936 l Claims. (Cl. 20G-150) This invention relates to electric circuit breakers, more particularly to those of the iiuid jet type wherein a blast ofvarc extinguishing :duid is projected across the arc, and has for its principal object the provision of an improved circuit breaker of the aforesaid type which shall be eillcient and positive in its interrupting effect throughout the entire range of current rating.

In accordance with this invention, the circuit is preferably opened at two points in succession,

and the arc at one point' is subjected vto a uid blast caused by arc generated pressure, and at the other point is subjected-to a uid blast effected by and in accordance with the circuit opening operation. In a modiiied form the arc at a single point is subjected to the combined blast effect of arc generated and piston created pressures. With this arrangement the heavy current arcs are interrupted by the arc generated blast, and the high voltage low current arcs, if not interrupted by the aforesaid means, are interrupted by the blast created by the circuit opening movement.

My invention will be more fully set forth in the following description referring to the accompanying drawings. and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and `forming a part of this specification.

Referring to the drawings, Fig. 1 is an elevational view, partly in section, of a high voltage electric circuit breaker embodying the present invention, Figs. 2 and 3 are similar views of a modified form of circuit breaker in the closed and partly open circuit positions respectively, Fig. i is a view similar toFlg. l showing another modified form of the present invention, Figs. 5 to 9 inclusive, are views of another modified form of the present invention, Figs. 10 and l1 illustrate diagrammatically the operation of the antireclosing device shown by Fig. 5 during the opening and closing operations respectively, Figs. 12, 13 ,and 14 are elevational sectional views of another form of circuit breaker embodying the present invention in the open, partly open and closed circuit positions respectively, and Fig. l5 is a similar view illustrating another modification for low current interruptions.

In certain types of high voltage electric circuit breakers, such as the well-known explosion chambertype wherein an arc generatedpressure causes expulsion of oil from` the chamber through the are, the interrupting perfomance may be tory at low or weak currents. On the other hand. the type of circuit breaker which depends solely upon a piston created iet of oil, for example, may have dimculty in interrupting high currents due to the counter-pressure created by the arc tending to oppose the operation of the piston.

The present invention overcomes the above difficulties so as to operate satisfactorily throughout the entire range of current rating by applying jets of iluid dielectric. which may comprise any suitable liquid or gaseous arc extinguishing medium, at the' -point or points of circuit interruption in a definite sequence. y With this arrangement. interruption of the circuit is insured by the second applied iet in the event that the first applied Jet is not eifective.

Referring more particularly to Fig. 1, there is. shown a high voltage vertical break oil circuit breaker comprising relatively movable contact structure adapted to form two breaksln series.

The nrst break is formed between the xed contact structure l anda movable intermediate contact 2, which are separable within an oil iilled explosion chamber l. The intermediate contact 2 is biased by a spring 4 away from the iixed contact I, its travel being limited by a shoulder 5 forming a stop.

'Ihe main movable contact structure, which forms the second break comprises a reciprocally movable operating rod l carrying a contact rod l. Secured to and movable with the contact rod 1 is an insulating piston structure l operable within a cylinder 9. The piston structure l comprises a cylindrical extension 8', the lower end of which is open and in communication with .the cylinder l, the upper part being closed at 8" except for ya central opening for receiving the contact extension ill oi' the intermediate contact. The piston structure 8 is also provided with insulating bailles forming an4 axial iluid passage II communicating with the cylinder 9 and transverse passages having exhaust nozzles at I2. 'I'he movable contact structure is operable through alined openings in the insulating piston 8 so that the passages i2 extend transversely thereof.

The breaker housing may comprise any suitable arrangement such as for example a ceramic insulating shell S mounted on a current transformer casing T at its lower end and carrying an cil baille B at its upper end for preventing oil throw.

very satisfactory at high currents due to the cor- When the circuit breaker is closed the operating rod 6 is elevated so that the rod contact l engages the intermediate contact 2 at ill, forcing the contact 2 upward against the bias of spring 4 until the circuit is completed at the fixed contact I.

In the opening operation the operating rod" 3 is lowered so that the intermediate contact 2,

During the circuit opening operation, however, y

the piston structure l has been descending within the cylinder 3 so as to force oil from the cylinder by way of the passages II and I2. Accordingly, when the second arc is drawn transversely oi' the passages I2, it is immediately subjected to positive transverse oil jets. This second application o! the oil jet is not dependent on the size o! the current to be interrupted and insures complete opening of the circuit, particularly in the case where the current is too weak to develop sumcient blast pressure within the explosion chamber 3.

The circuit breaker shown by Figs. 2 and 3 comprises a nxed contact I3 yand an intermediate movable contact I4 which is secured to and carried by the insulating operating rod I5. As illustrated by Fig. 2, the breaker is in the closed circuit position. Movable with the contact I 4, which is electrically connected to a conducting block I5, is an insulating cylinder I1 coacting with a fixed piston member I3. The piston Il is carried by a conducting tube I 9 which is iixed and which also carries an annular xed contact 20. In sliding conducting engagement with the contact 2l is the contact 2l which is carried by the cylinder I1 and which is electrically connected by a conductor 22 to the intermediate contact structure I4-I8.

At the upper end of the cylinder I1 there are formed by the insulating structure 24, transverse jet passages communicating at one end through the axial passage 23 with the cylinder I1 and terminating at the exhaust nozzles 25.

In the closed circuit position shown by Fig. 2 the circuit is completed through the fixed contact I3, coacting movable contact structure I4-IB, conductor 22, contacts 2li and 2l and the xed conducting tube I9 which is suitably connected to the lower breaker terminal.

When the breaker is opened, the rod I is lowered so as to cause separation of the contacts I3 and I4. coincident with the opening movement, the oil within the chamber 26 is subjected to pressure by the relative movement of the cylinder I1 and piston I8 resulting in on oil jet through the passages 23 and 25 transversely of the arc between contacts I3 and I4 as illustrated by Fig. 3.

As the opening operation progresses, lowering of the cylinder lI1 nally causes separation of the contacts and 2i within a chamber dened by the lower part of the cylinder I1 and the piston I3. In the event that the arc formed by the contacts I3 and I4 and has not been extinguished, which may occur in case a heavy current is to be interrupted, a second arc in series with the first arc is formed between contacts 20 and 2|.

There is then produced below the piston Il within the chamber 21 a high arc generated pressure which causes immediate acceleration of the downward travel of the cylinder I1 so as to augment the force oi the oil. jet transversely of the arc at 25. This added force applied to the transverse oil jet insures complete opening of the circuit since the arc generated pressure is approximately proportional to the arc current.

The circuit breaker illustrated by Fig. 4 is generally similar in principle to the breaker shown by Fig. l and comprises a xed contact 28 and a coac-ting intermediate contact 23 which is biased by a spring 30 away from the xed contact. The intermediate contact 23 which also coacts with the movable contact rod 3I carries a piston member 33 which is operable within a fixed insulating cylinder 34. Apertures 35 in the'piston are controlled by ilap valves 36 for admitting oil to the lower part of the cylinder during the circuit closing operation. The travel of the intermediate contact 2l is limited by abutments at 31 on the cylinder 34.

When the breaker is to be operated from the open circuit position shown by Fig. 4, to the closed circuit positioh, the operating rod 32 is elevated so as to cause the rod contact 3| to engage the intermediate contact 23 and move the same against thebias of spring 3| into engagement with the fixed contact 23.

When the breaker is opened, the rod 32 is lowered and the intermediate contact, which follows for a limited distance the contact 3|, separates from the xed contact 23. Separation oi the contacts 2l and 23 takes place within a known form of cross jet explosion chamber including an axial passage 33 in communication with the arc pressure at the contact 2B and with passages exhausting at 39 transversely of the arc.

Under certain conditions interruption of the circuit takes place within the transverse passages 39. The descent o! the intermediate contact 29 under bias of the spring 30,4however, is somewhat slower than the descent of the contact 3| due to the piston 33 with the result that a second break is formed between the contacts 23 and 3l. If, at this time, the circuit is not interrupted at the rst point, the second arc formed between the contacts 29 and 3l is subjected to a transverse jet by way of the passages 43 and 4I due to the descending piston 33. Accordingly, if the arc at the rst break is not interrupted by the arc generated blast through the transverse passages 3S, the circuit is very shortly thereafter interrupted by a piston driven jet directed through the second arc at the transverse passages 4I.

Fig. 5 illustrates another form of circuit breaker generally similar in principle to that shown by Figs. 2 and 3. The breaker comprises a main nxed contact 42 and a coacting movable rod contact 43 to which is secured an insulating piston structure 44 operable Within a cylinder 45. The piston 44, as in the case of Fig. 1, includes an extension 44' which is open at its lower end in direct communication with the cylinder 45. The upper end of the piston structure is closed except for a central aperture for receiving the contact 42 and a fluid passage formed by an aperture 4B communicating with the cylinder 45 and a transverse passage 41 extending transversely of the path of separation of the contacts 42 and 43.

It will be noted that the diameter of the contact portion of the rod contact 43 is smaller than that of the main operating extension 4B. This diierence in diameter enables the lower part of 21,848 the rod contact, viz. at 49, to make separate engagement with a ilxed annular contact 49. In the closed circuit position the contact portions 4I and 49 are in engagement as well as the contacts 42 and 42.

In the opening operation the rod 49 is lowered by a suitable linkage indicated at 49' and the piston structure 44 in descending into the cylinder 45 directs a transverse jet through the arc at 41 in the manner previously described. Also, it will be noted that after a predetermined separation of the contacts 42 and 4I the contacts 49 and 49 also separate thereby forming two breaks in series. If the arc at contacts 42 and 49 is not extinguished, a second arc will form between contacts 4I and 49 thereby increasing the pressure beneath the piston 44. An insulating sleeve 50 is secured to the fixed contact structure and guides the contact 45. 'I'his is best illustrated by the enlarged view in Fig. 6 wherein the arc for-med between contacts 49 and 49 is indicated at 5|.

The arc generated pressure in the cylinder 45 acts to increase the effectiveness of the oil jet. Accordingly, as in the previous cases a piston created oil iet initiated by and in accordance with the circuit-opening operation is effective to' interrupt comparatively light or moderate currents. and a force corresponding to the magnitude of the current to be interrupted is further applied to the oil .iet in the event that the arc is not interrupted by the first jet.

It may be advantageous to provide the sliding contacts 49 and 49 with arc shields so that the normal contact engaging surfaces are not subjected to the arc. Fig. 7 is an enlarged view illustxating such an arrangement, the arc shields 52 and 53 being annular in form and connected to the contacts 49 and 49 respectively. Fig. 7 illustrates the contacts in the closed circuit position, and Fig. 8 illustrates the operation of the arcing portions in the circuit opening operation.

Where it is -advantageous to limit the length of arc in order to prevent excessive arc pressure, as for example, to a distance approximately equal to the radial clearance r between the contacts 43 and 49. the arc shield 53 is provided with an annular arcing horn 54 as shown by Fig. 9. The arcing shield 52 may be provided with a similar arcing portion if desired.

In view of the high pressure which is developed in the cylinder 45 by the arc at 5|, it may be necessary to provide the operatingmechanism of the circuit breaker at 48' with an interlocking device which will prevent the mechanism from reversing its movement, thereby tending to reclose the breaker during the opening operation. Any suitable device can be used to this end. Figs. 5. and 11 illustrating a particularly simple and effective interlocking device.

The interlocking device consists of a cam which is rotatably mounted at a fixed pivot 55, the cam comprising a main portion 55 having a shoulder 51 which is adapted to engage a roller 59 carried by a rod 59 which is suitably connected to the operating mechanism 49'. Since the rod 59 is actuated during the opening `operation in the direction indicated by the arrow at 55 (Fig. 5), the interlocking mechanism assumes successively the positions a. to j of Fig. 10. These positions illustrate the elevational views as in Fig. 5.

It will, therefore. be seen that the follow-up roller 59 first lifts the cam 55 about its pivot 55 and then when it reaches position c the cam drops behind the roller. In this position, which corresponds to separation of contacts 49 and 49,

the roller is prevented fromV reversing its movement by the cam surface 51, and reverse or reclosing movement of the breaker is thereby precluded. As the opening movement continues the roller lifts the pivoted flap member 5| which is carried by the cam and moves past the flap finally assuming a position indicated at f.

In the closing operation, which is indicated by the directional arrow 52 of Fig. 11, the roller 59 assumes successively the positions g, h, i and j. The .flap 5| which is freely hinged on the cam (position h.) enables the roller to lift the cam past the blocking surface 51 so that the roller can pass without obstruction beneath the cam.

Figs. 12, 13 and i4 illustrate another form of circuit breaker wherein the-piston structure for creating the oil blast in accordance with the circuit opening operation is mounted for limited movement with respect t0 the movable contact structure. In this arrangement but one break is necessary for subjecting the arc to both an arc generated blast and a piston created blast.

Referring to Fig. l2 the single break is formed between the movable contact 54 associated with the insulating piston structure 63 and the fixed contact 55. The fixed contact is also associated with an insulating oil jet chamber having a passage 55 communicating with the arcing space and transverse passages terminating at 51. The chamber is also provided with a central passage in alinement with the contacts 64 and 55. The oil jet chamber above described functions in substantially the same manner as the corresponding structure of Fig. 4 to interrupt the arc between the contacts 64 and 55 by an arc generated cross blast.

The plunger type piston 53 which is mounted for limited sliding movement; on the contact 54 operates within a fixed cylinder 59. As in the previous instance the piston has formed therein a passage 59 communicating with the cylinder and with transverse passages extending across the path of the movable contact and terminating at 10. T'he movable contact 54 is suitably connected to the corresponding breaker terminal through a xed contact 1|.

Fig. 12 illustrates the breaker in the open-circuit position, the movable contact rod 54 being held in its lower position against the bias of a spring 12. The spring 12 in this position holds the piston structure 53 against a stop member 18 of the movable contact so that the piston and contact move together during the latter part of the opening stroke and the first part of the closing stroke.

In the closing operation, which is illustrated by Fig. 13, the contact rod 54 is elevated carrying with it under bias of spring 12 the piston structure 53 until the piston engages the upper oil jet chamber. During the latter part of the closing stroke the contact 54 moves independently of the piston structure through the alined contact openings to engage the fixed contact 55 as illustrated by Fig. 14.

In the opening operation the contact 54 is lowered and during the initial travel thereof the arc between the contacts 54 and 65 is subjected to an arc generated blast through transverse passages 51. When the stop member 13 reaches the lower part of the piston from that point on the piston moves as a part of the movable contact structure so as to project an oil blast through the arc at the passages 10.

In the above-described arrangements the oil jets which are intended to insure under all conditions the interruption of the arc have been assumed to be produced by a piston type compressor. It will be/understood, of course, that any other equivalent means may be utilized which is actuated by the operation of the movable contact structureof the breaker. When the interruption of comparatively weak currents only is involved, correspondingly low velocit)r oil blasts can be used. Such low velocity oil jets can be simply produced by the action of oil, which is comparatively statlonary in the circuit breaker tank, on the rod of the movable contact when the crater or root of the arc is switched over to the side of the rod.

A simple arrangement of this character is shown by Fig. 15 wherein the iixed contact 1I is surrounded by a ilxed oil .jet chamber 15 having transverse oil jets similar to those of Il and 61 of Fig. 12. Here the movable contact rod 16 carries a terminal extension 1.1 composed of arc-resisting insulating material. In the closed circuit position the extension 11 enters the contactl 1l which is annular in form so that the circuit is closed at the sides of the contact rod 16. In operation the arc .necessarily strikes between the contact 1l and a lateral side of the contact 1B, the crate or root of the arc 18 being indicated at 19. The side wash of the oil on the crater of the arc at 1I is sufilcient to interrupt the arc in the case of weak currents.

It shall be understood that the present invention is not limited to any predetermined sequence of operation of the arc generated blast and the piston created blast. That is, the particular operating requirements and interrupting characteristlcs can be determining as to whether the arc generated blast precedes the piston created blast.

It should be understood that my invention is not limited to specific details of construction and arrangement'thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit oimy invention. e

What lI claim as new and desire to secure by Letters Patent of the United States is:

l. An electric circuit breaker of the iluid blast type comprising relatively movable contact structure, an arc-extinguishing fluid, and means for extinguishing arcing at said contact structure upon opening of the circuit including insulating structure movable in accordance with the circuitopening operation, forming fluid passages adapted to traverse portions of the arc path, said insulating structure also including a piston for directing arc-extinguishing fluid through said passages for interrupting the circuit.

2. An electric circuit breaker of the fluid blast type comprising relatively movable contact structure, an arc-extinguishing fluid, and means for extinguishing arcing'at said contact structure upon opening of the circuit including insulating structure forming iluid passages adapted to traverse portions of the arc path, said insulating structure also including a piston disposed within a casing containing said arc-extinguishing fluid, means for actuating said insulating structure in accordance with the circuit opening operation for forcing said fluid through said fluid passages, and means for also directing arc generated pressure for eiecting the arc-extinguishing operation.

3. An electric circuit breaker of the fluid blast type comprising relative movable contact structure adapted to form two breaks in series, an arcextinguishing uid, insulating baille structure 21,848 A througlrwhich the arc at one ofA said breaks is drawn and a piston connected to said movable contact structure for confining and subjecting respectively the arc at said one of said breaks to an arc-extinguishing blast of iluid in accordance with' the circuit opening operation, and Ameans ior utilizing arc pressure generated at the other break for also extinguishing arcing.

4. An electric circuit breaker oi' the fluid blast type comprising relatively movable contact structure adapted to form two breaks in series, an are extinguishing) iluid, means forming an arc-interrupting chamber arranged for confining arc pressure so as to cause a blast of arc-extinguishing fluid from said chamber in response to formation oi' the arc, one of said breaks being formed within said chamber, and piston structure operable in accordance with the circuit opening operation for directing arc-extinguishing fluid through the arc at said other break.

5. An electric circuit breaker of the fluid blast type comprising relatively movable contact structure adapted to form two breaks in series, an arc-extinguishing fluid, and an arc chamber within which one of said breaks is initially formed, said chamber arranged to confine arcgenerated pressure for causing a blast of arcextinguishing fluid the arc, and an insulating bale coacting with a pistonl movable in accordance with the circuit opening operation at the subsequently formed break for directing arc-extinguishing fluid through said break for interrupting the circuit in the event that it is not interrupted within said chamber.

y6. An electric circuit interrupter of the fluid blast type comprising relatively movable contact structure, an arc-extinguishing fluid, and

means for extinguishing arcing at said contact said -insulating structure structure upon opening of the circuit comprising means for directing arc generated pressure so as to cause a blast of arc-extinguishing fluid through one portion of the arc, and insulating structure movable -with said contactY structure forming a iiuid passage adapted to traverseanother portion of the arc path, and a piston also connected to said movable contact .structure adapted to force arc-extinguishing fluid through said passage. 'Y

7. An electric circuit interrupter of the fluid blast type comprising relatively movable contact structure adapted to form two breaks in series, an arc-extinguishing fluid, means forming an arc chamber'yvithin which one of said breaks is formed, said achamber arranged to direct arc generated pressure sowas to cause an arc-extinguishing fluidblast, insulating piston structure forming fluid passages adapted to extend transversely of the arc path at the other oi' said breaks, said last-named break being formed subsequently to said other break. andmeans relating said piston structure to themovable contact structure so that arc-extinguishing fluid is forced through said passages in accordance with the circuit openingoperation for interrupting arcing at said subsequently formed break.y

8. An electric circuit breaker of the fluid blast type comprising relatively movable contact structure adapted to iorm two breaks in series, an arc-extinguishing fluid. insulating structure forming fluid passages adapted to traverse the path of the arc at one of said breaks, said insulating structure being operable as a piston in accordance with the circuit opening operation for forcing arc-extinguishing fluid through said pasimm said chamber throughl sages, and means for directing arc pressure generated at the other of said breaks so as to augment the aforesaid arc-extinguishing blast.

9. An electric circuit breaker of the iiuid blast type comprising relatively movable contact structure adapted to form two breaks in series, an arcextinguishing iiud, piston structure forming a passage adapted to extend transversely o! the arc path at one of said breaks, said piston structure movable in accordance with the circuit opening operation for driving arc-extinguishing iuid through said passage, means for directing arc pressure generated at said other break so as to increase the fluid pressure at said piston structure, and means operable upon the formation oi said last-named break for blocking reverse movement of said contact and piston structure whereby said arc generated pressure is effective to augment the fluid blast at said first-named break.

10. An electric circuit breaker oi the uid blast Cil type comprising relatively movable contact structure, an arc-extinguishing iiuld, means for extinguishing arcing at said contact structure upon opening of the circuit comprising insulating structure forming iluid passages adapted to traverse portions of the arc path, said passages being arranged so that arc generated pressure causes an arc-extinguishing blast therefrom, a second insulating structure forming iiuid passages adapted to traverse other portions oi' the arc path, said second insulating structure being relatively movable with respect to said first insulating structure, opening of the circuit initially causing arcmg in said first insulating structure, and means for actuating said second insulating structure as a piston in accordance with the circuit opening operation so as to force arc-extinguishing iiuid through the passages therein for interrupting arcing.

GEORGES BALA'CHOWSKY. 

